1. Department of Informatics, Kindai University, Higashihiroshima, Hiroshima, Japan
2. Institute for Q-shu Pioneers of Space, Inc., Fukuoka, Japan
3. Computer Vision Research Team, Artificial Intelligence Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan
4. Department of Endoscopy-, Hiroshima University Hospital, Hiroshima, Hiroshima, Japan
5. Graduate School of Biomedical & Health Sciences, Hiroshima University, Hiroshima, Japan
6. Graduate School and Faculty of Information Science and Electrical Engineering, Kyushu University, Fukuoka, Japan